Now THAT's the answer I need. Thank you for the pointer. BTW: we live in the high desert of New Mexico where black driveways are uncommon. They are hot, always dirty, ugly and, well, too dark for the surrounding desert landscape. Once or twice a year a black asphalt driveway helps snow melt faster, but by far the larger portion of our year is spent in sunshine. Outside of having the thing dug up, we have little option but to live with it or do something creative about it. Thanks for answering my question!